FLASH及FLAIR序列在脑弥漫性轴索损伤中的诊断价值

目的 探讨MR快速小角度激发梯度回波(FLASH)序列及液体衰减反转恢复(FLAIR)序列在脑弥漫性轴索损伤(DAI)中的诊断价值.资料与方法 回顾性分析40例经临床诊断的DAI患者的MR影像资料,所有患者均行T1WI、T2WI、FLAIR及FLASH序列扫描.比较各序列脑内病灶的显示率,分析其信号特征.结果 FLASH序列显示病灶最多、最敏感,病灶主要分布在皮髓交界区、基底节、胼胝体、脑干及小脑等区域,呈散在针尖状、斑点状、结节状、小片状中央显著低信号,周围薄环状高信号,FLAIR序列只有部分病灶显示,为结节状、斑片状高信号,且病灶越小显示越不敏感,常规T2WI较FLAIR序列敏感性差,常规T1WI显示率最低,显示者T2WI为高信号,T1WI为低信号.结论 对DAI病灶检出率FLASH、FLAIR序列较常规T2阢、T1WI高,可为DAI早期诊断、早期治疗提供科学、客观的影像学资料,对临床疑有DAI患者FLASH、FLAIR序列应作为MR检查的常规序列,FLASH序列为首选序列.

The Value of FLASH and FLAIR Sequence in Diagnosis of Diffuse Axonal Injury

Objective To assess the value of FLASH and FLAIR sequence in diagnosis of DAI(diffuse axonal injury).Materials and Methods The MRI data of 40 cases with DAI diagnosed by clinic were analyzed retrospectively.All the patients underwent MRI examination with SE,FLASH,FLAIR sequences.The signal intensity features and detection rate of lesions were compared in all sequences.Results FLASH sequence detected more lesions than that in other sequences.DAI lesions located in the junctional zone of cortex and medulla,basal ganglia,corpus callosum,brain stem and cerebellum.The MR features of the DAI showed in FLASH were hypointensity signal in shape of needle tip,mottling,nodular,patchy surrounded by a thin circle of hyperintensity signal.FLAIR detected some lesions,and the MR features were hyperintensity signal in shape of nodular,patchy.SE T2W sequence had the lowest sensitivity,and DAI showed as long T1 long T2 signal.Conclusion FLASH and FLAIR have higher sensitivity than that in SE sequence,and can provide more image information for the diagnosis and treatment of DAI,which should be used as the routine sequence in the MRI examination for the patients who suspiciously have DAI,and FLASH sequence is the first choice.